This invention concerns a dishwasher for washing dishes.
In a well-known common type of dishwasher, a wash water supply means such as a circulation pump is used, a nozzle body is rotated, and the wash water is sprayed from spray apertures in the nozzle body onto the dishes in a wash tank. FIG. 1 and FIG. 2 illustrate an example of this type of dishwasher.
As illustrated in FIG. 1 and FIG. 2, the dishwasher includes a wash tank 1 containing a cage 3 for accommodating dishes 2. A nozzle body 5 is provided in the wash tank 1 and rotates under hydraulic pressure supplied by a circulation pump 4. Wash water from a plurality of spray apertures 6 on the nozzle body is sprayed onto the cage 3, and the dishes 2 are thereby washed. Wash water that is to be used in the wash tank is first collected at the bottom of the tank 1 by a water supply device (not shown), and while being heated by a heater or other heating means (not shown), passes through a residue filter 8, returns to the circulation pump 4, and is then re-sent to the nozzle body 5.
In the conventional type of dishwasher described above, wash water is sprayed through the spray apertures while the nozzle body 5 rotates, but as shown in FIG. 2, wash water is not distributed evenly between the corners CN and the central part CP of the wash tank 1 regardless of how the angle of spray from the apertures 6 may be adjusted. Moreover, the dishes in the cage 3 may have different shapes, and as they cannot be set in the cage under the same conditions with respect to the nozzle body 5, they cannot be washed uniformly. In order to prevent this, the wash tank 1 must have a shape which is as close to a square as possible or else be circular having its center coincident with the center of rotation of the nozzle body 5, and the dishes 2 must be set at an equal distance from the center of rotation. Gaps must also be left between the dishes where the water cannot easily enter. The gaps are left, however, the space taken up by the dishes is then greater, the wash tank 1 has to be made larger, and the dishwasher cannot be made compact. Further, it was found that dishes 2 set at the corners CN were not washed clean unless the washing time was extended.